Molecular weight development during simultaneous chain scission, long-chain branching and crosslinking, 2 - Free-radical polymerization

The matrix formula developed in Part 1 of this series is applied to describe the molecular weight development during free-radical (co)polymerization. All of the required probabilistic parameters are expressed in terms of the kinetic rate constants and pertinent concentrations. In free-radical polymerization, the primary chains are formed consecutively. The segments that constitute nonlinear polymer molecules are divided into N fractions on the basis of the birth conversion levels, and the weight-average molecular weight of the whole reaction system is obtained by extrapolation N to infinity. Practically, such extrapolation can be conducted by using the calculated values for only three different N values with sufficient accuracy. In the context of the present theory, not only the full molecular weight distribution but also the polymer structure formed can be determined directly by using the Monte Carlo simulation method.